A potential anti-Helicobacter pylori strategy: Exploring the antibacterial mechanism of organic acids in sea buckthorn (Hippophae rhamnoides L.).

Helicobacter pylori (H. pylori) infection is a highly prevalent causative agent of various gastric diseases. The search for natural alternatives to antibiotics that can effectively inhibit H. pylori has become a pressing concern. In the present study, the potential anti-H. pylori activity of organic acids in sea buckthorn was investigated. Sea buckthorn organic acid extracts (SOA) inhibited H. pylori growth at a minimal inhibitory concentration of 10 mg/mL. Oxalic, tartaric, L-malic, ascorbic, lactic, citric acid were detected in SOA with the concentration of 0.512, 14.446, 13.111, 2.699, 0.303, 1.822 mg/g, respectively. Notably, malic, oxalic and tartaric acid had pronounced anti-H. pylori properties by inhibiting biofilm formation, increasing outer membrane permeability, disrupting membrane integrity, decreasing urease activity and altering membrane protein conformation. The three organic acids could suppress H. pylori urease genes (ureA, ureB), virulence genes (VacA, CagA), replication genes (dnaE, dnaN, dnaQ), transcriptional genes (rpoA, rpoD, rpoN), motility genes (flhA, flaA, flgE), adhesion genes (alpA, alpB, hpaA, hpaZ) and outer membrane protein genes (BabA), and had an inhibitory capacity on VacA and CagA protein expressions. Furthermore, three organic acids may reduce the production of pro-inflammatory factors including interleukin-1β (IL-1β), IL-6, IL-8 and reactive oxygen species (ROS) in H. pylori-induced GES-1 human gastric mucosal epithelial cells, contributing to the amelioration of inflammation induced by H. pylori infection. It might provide a theoretical basis for subsequent animal and clinical trials, and potentially be applied as a promising value-added food ingredient candidate for protecting human against gastric diseases caused by H. pylori infection.